Three native Pseudomonas fluorescens strains tested under growth chamber and field conditions as biocontrol agents against damping-off in alfalfa

Alfalfa (Medicago sativa) is one of the most important crops used in Uruguay for livestock feeding. Seedling diseases, particularly damping-off, are a critical factor which limits its establishment. Three native Pseudomonas fluorescens strains, UP61.2, UP143.8 and UP148.2, previously isolated from Lotus corniculatus, were evaluated to determine their efficacy as biological control agents for alfalfa seedling diseases in the field. Their compatibility with the alfalfa-Sinorhizobium meliloti symbiosis was also assessed. In growth chamber conditions seed inoculation with Pseudomonas strains did not affect different parameters of alfalfa-rhizobium symbiosis as shown by nodulation rate and shoot dry weight of plants. The presence of the commercial inoculant strains of S. meliloti did not impair colonization by the P. fluorescens and vice versa. In field trials the dynamics of rhizobial rhizospheric populations were not affected by the presence of P. fluorescens. Each P. fluorescens strain successfully colonized alfalfa roots at adequate densities for biocontrol activity. Results showed that P. fluorescens strains provided a 10–13% increase in the number of established plants relative to the control, an intermediate result compared to the fungicide treatment (24%). The alfalfa above-ground biomass was increased by 13% and 15–18% in the presence of the fungicide and P. fluorescens strains, respectively. Therefore, results from this study demonstrated that the three P. fluorescens strains provided effective control against soil-borne pathogens and suggest a potential use in the development of a commercial inoculant to be applied for the control of legume seedling diseases.     

Heterologous Expression and Characterization of an Alcohol Dehydrogenase from the Archeon <Emphasis Type="Italic">Thermoplasma acidophilum</Emphasis>

Analysis of the Thermoplasma acidophilum DSM 1728 genome identified two putative alcohol dehydrogenase (ADH) open reading frames showing 50.4% identity against each other. The corresponding genes Ta0841 and Ta1316 encode proteins of 336 and 328 amino acids with molecular masses of 36.48 and 36.01 kDa, respectively. The genes were expressed in Escherichia coli and the recombinant enzymes were functionally assessed for activity. Throughout the study only Ta1316 ADH resulted active in the oxidative reaction in the pH range 2–8 (optimal pH 5.0) and temperatures from 25 to 90°C (optimal 75°C). This ADH catalyzes the oxidation of several alcohols such as ethanol, methanol, 2-propanol, butanol, and pentanol during the reduction of the cofactor NAD⁺. The highest activity was found in the presence of ethanol producing optically pure acetaldehyde. The specific enzyme activity of the purified Ta1316 ADH with ethanol as a substrate in the optimal conditions was 628.7 U/mg.     

Photoactivation of trans diamine platinum complexes in aqueous solution and effect on reactivity towards nucleotides

We show that UVA irradiation (365 nm) of the Pt^IV complex trans,trans,trans-[Pt^IVCl₂(OH)₂(dimethylamine)(isopropylamine)] (1), induces reduction to Pt^II photoproducts. For the mixed amine Pt^II complex, trans-[Pt^IICl₂(isopropylamine)(methylamine)] (2), irradiation at 365 nm increases the rate and extent of hydrolysis, triggering the formation of diaqua species. Additionally, irradiation increases the extent of reaction of complex 2 with guanosine-5′-monophosphate and affords mainly the bis-adduct, while reactions with adenosine-5′-monophosphate and cytidine-5′-monophosphate give rise only to mono-nucleotide adducts. Density Functional Theory calculations have been used to obtain insights into the electronic structure of complexes 1 and 2, and their photophysical and photochemical properties. UVA-irradiation can contribute to enhanced cytotoxic effects of diamine platinum drugs with trans geometry.     

Cytoplasmic FMR1 interacting protein (CYFIP) family members and their function in neural development and disorders

Molecular Biology Reports - In humans, the cytoplasmic FMR1 interacting protein (CYFIP) family is composed of CYFIP1 and CYFIP2. Despite their high similarity and shared interaction with many...     

The role of glucose metabolism and insulin resistance in cardiac remodelling induced by cigarette smoke exposure

The aim of this study is to evaluate whether the alterations in glucose metabolism and insulin resistance are mechanisms presented in cardiac remodelling induced by the toxicity of cigarette smoke. Male Wistar rats were assigned to the control group (C; n = 12) and the cigarette smoke-exposed group (exposed to cigarette smoke over 2 months) (CS; n = 12). Transthoracic echocardiography, blood pressure assessment, serum biochemical analyses for catecholamines and cotinine, energy metabolism enzymes activities assay; HOMA index (homeostatic model assessment); immunohistochemistry; and Western blot for proteins involved in energy metabolism were performed. The CS group presented concentric hypertrophy, systolic and diastolic dysfunction, and higher oxidative stress. It was observed changes in energy metabolism, characterized by a higher HOMA index, lower concentration of GLUT4 (glucose transporter 4) and lower 3-hydroxyl-CoA dehydrogenase activity, suggesting the presence of insulin resistance. Yet, the cardiac glycogen was depleted, phosphofructokinase (PFK) and lactate dehydrogenase (LDH) increased, with normal pyruvate dehydrogenase (PDH) activity. The activity of citrate synthase, mitochondrial complexes and ATP synthase (adenosine triphosphate synthase) decreased and the expression of Sirtuin 1 (SIRT1) increased. In conclusion, exposure to cigarette smoke induces cardiac remodelling and dysfunction. The mitochondrial dysfunction and heart damage induced by cigarette smoke exposure are associated with insulin resistance and glucose metabolism changes.     

Supplement comprising of laccase and citric acid as an alternative for antibiotics: In vitro triggers of melanin production

An indiscriminate use of antibiotics in humans and animals has led to the widespread selection of antibiotic‐resistance, thus constricting the use of antibiotics. A possible solution to counter this problem could be to develop alternatives that can boost the host immunity, thus reducing the quantity and frequency of antibiotic use. In this work, for the first time, citric acid and laccase were used as extracellular inducers of melanin production in yeast cells and human cell lines. It is proposed that the formulation of laccase and citric acid together could further promote melatonin‐stimulated, melanocyte‐derived melanin production. Melanization as a probe of immunity described in this study, is an easy and a rapid test compared to other immunity tests and it allows performing statistical analyses. The results showed the synergistic effect of citric acid and laccase on melanin production by yeast cells, with significant statistical differences compared to all other tested conditions (p: 0.0005–0.005). Laccase and citric acid together boosted melanin production after 8 days of incubation. An increase in melanin production by two human colon cells lines (Cacao‐2/15 and HT‐29) was observed on supplementation with both laccase and citric acid in the cell growth medium. Produced melanin showed antimicrobial properties similar to antibiotics. Therefore, a formulation with citric acid and laccase may prove to be an excellent alternative to reduce the antibiotic use in human and animal subjects.     

Synthetic peptides derived from an N‐terminal domain of the E2 protein of GB virus C in the study of GBV‐C/HIV‐1 co‐infection

Synthetic peptides derived from GB virus C (GBV‐C) have previously been studied in our group for the development of new systems capable of diagnosing diseases caused by this humanotropic virus. We also recently described specific peptide domains of the E2 envelop protein of GBV‐C that have the capacity to interfere with the HIV‐1 fusion peptide, produce a notable decrease in cellular membrane fusion, and perturb HIV‐1 infectivity in a dose‐dependent manner. The present work discloses the design and synthesis of both linear and cyclic branched peptides based on a previously reported N‐terminal sequence of the GBV‐C E2 protein. Immunoassays and cell–cell fusion assays were performed to evaluate their diagnostic value to detect anti‐GBV‐C antibodies in HIV‐1 patients, as well as their putative anti‐HIV‐1 activity as entry inhibitors. Our results showed that chemical modifications of the selected E2(7–26) linear peptide to afford cyclic architecture do not result in an enhanced inhibition of gp41 HIV‐1‐mediated cell–cell fusion nor improved sensitivity in the detection of GBV‐C antibodies in HIV‐1 co‐infected patients. Thus, the ELISA data reinforce the potential utility of linear versions of the E2(7–26) region for the development of new peptide‐based immunosensor devices for the detection of anti‐GBV‐C antibodies in HIV‐1 co‐infected patients. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.